Variable-speed gear



April 12, 1949. B. w. BARLOW VARIABLE SPEED GEAR 5 Sheeis-Sheec 1 Filed Nov. 29, 1946 t BMIIWN 4!!! l L cl Attorney April 12, 1949.

Filed NOV. 29, 1946 B. w. BARLOW 2,467,108

VARIABLE SPEED GEAR 5 Sheets-Sheet 2 I mentor BEman/u in-um Bnnww v wug/wwmmw Altorney April 12, 1949. B. w. BARLOW VARIABLE SPEED GEAR' 5 Sheets-Sheet 3 Filed NOV. 29, 1946 A liorney By Mia April 12, 1949.

B. W. BARLOW VARIABLE SPEED GEAR 5 Sheets-Sheet 4' Filed NOV. 29, 1946 I I n to: Bum/m1 Wm. u n ww By W 0364;,

Attorney April 12, 1949. B. BARLOW 254672108 VARIABLE SPEED GEAR Filed Nov. 29, 1946 5 Sheets-Sheet 5 [ii Un [or BEA/JAMIN Mn. B

"I ww l A ("IN Patented Apr. 12, 1949 UNITED STATES. PATENT OFFICE Application November 29, 1946, Serial ri -712.303

' In Great Britain Qctober'ZSl, 1935 This invention'relates to variableispee d gears of the type in which gearwheelsfa'st'on'a drivin shaft are in constant meshwith gear wheels which are loose on a driven shaft to which these wheels can be selectivelyv connected by' 'clutches and has for its object to provide improvedmeans for controlling'these "gearfselecting clutches and effecting a change 'in'fthe transmission speed. While the invention isapplicable to speed gears of this type as emp oyed'rorvarious pu'rpo'sesit' ismore especially intended for-use with variable speed gearing bywhich the impelle'ri'of a supercharging' compressor iselriven,

According to this invention the; disengagement of one gear selecting clutch and the engagement 'of another gear selecting-clutchfor the purpose of altering the gear ratio 'inthe-trarismission-tothe driven shaftis effected by: causing the driven shaft to rotate at a speed in ex'cesspftha'fiatfwlrich it can be driven at the higher gear ratio and through theclutchwhich brings that gear into operation. The engagement and disengagement of a clutch is effected by causing relative rotation between one of the members that clutch and a part on whichitis carried- -Thisrelative rotation will 1 cause a movement of that: clutch member in the axial direction. Means areprovided whereby one clutchafter it has beendisengaged can be so maintainedand re enga'gement prevented while the drive is transmitted through another clutch and'the g-ear'wheelswith which it is associated. Relative rotation between one of the members of a clutchandthepart'on which itis carried and-achange in the gear ratio .to be broughtabout isfeifected through ajduid in excess of megawa t it can be driven at which brings that gear intooperation. H The apparatus may be arranged in various the higher gear ratio and" throughthe clutch ways and the "details modified inaccordance with ing constructed for "the transmission ef 3 or more different spe'd;'i T1,; 1

I i; The" accompanying' draWingfs illustrateby way of .iexainple'i the. invention in-a const ructiori' in which there are rtwm'alternative speed ratios such asimay befadoptedwhen.Jcarryihgithe inv' en on into practice. In.thes;dra'wings' l. i Figure. .1; is. a diagrammatic view'in "which Ith principal featuresembodied.in.the.improved..variablespeed gear are indicated,

nail owing to the interengaging ction 1,, Pubiic Law 690, August 8, 1946 I j Patent expires October 29, 1965 v 7 Claims. 01. 74665) 2 Figure 2 is a longitudinal sectional elevation of a construction. embodying the improved variable speed gear and showing the partsas when the higher gear ratio is engaged. I

Figuref3 is a similar view showing the parts when the lowergear ratio is engaged. 1 f Figure 4 is a transverse section on the line 4-4 'in Figure 2 looking inthe direction of the arrows. Figure 5 isa transverse section on the line 5 5 in Figure Mocking in the direction of the arrows.

\ Figure 6 is atran'sverse section on the line 6-6 inFigure 2 looking in the direction of the arrows.

- Figure '7 is a transverse section on the line 1- -1 inFigu're 3 looking in the direction of the arrows. Referring to theidiagrammatic view in Figure 1, this illustrates anarrangement in which there are two speed ratios and the gear'is adapted for driving the impeller of a 'supercharging compressor. In such an apparatus the driving shaft A to 'which rotationis imparted from a suitable source of power, has fixed thereon three gear wheels of different sizes, namely a small wheel B, an intermediate sized wheel C and a large wheel D. The driven shaft E is parallel to the driving shaft A and has at one end an impeller F. Carried loosely on the shaft E are three gear wheels respectively meshing with the three'wheels on the driving shaft, namely a large wheel-G meshing with the smallest wheel B on the driving shaft A, an intermediate wheel H meshing with the intermediate wheel C, and a small wheel 'J'm'eshing with the largestiwheelD on the driving shaft. .Both'the largest wheel G and the intermediate wheel H on the .driven shaft E respectively carry clutch members G and H of suitable form through which each wheel can be coupled to the driven shaft E. The clutch members K and L on the driven shaft which cooperate with the clutch members G H are connected to the shaft E through p'arts respectively on the shaft and 'withineach clutch member having helical splines or quick-pitch threads, these parts E, E with pitches of oppositehand on the shaft being indicated in Figure 1. Thus if one of the clutches is engaged and the shaft E is thereby rotated at the speed determined by the gear set which is then operative, and it is then desired to change this speed, the clutch can be disengaged andthe. change effected by causing the dr ven shaft E to rotatetemporarily at a greater speed. This will result in. the shaft E turning relatively .t0-.the clutch member thereon and the lag of the latter due to its inertia will cause this clutch member to move in the axial direction on the quick-pitch 3 threads on these parts. In this way either of the clutch members L or K will be withdrawn from its corresponding clutch member G or H on the wheels G and H. Conveniently the lagging of a clutch member on the shaft Elisfassisted by providing the loose wheels G and H on their clutch parts G H with a part which is in frictional contact with the clutch member K or L or some other part connected to the shaft'E. By this means a braking effectis exerted on the clutch member and its rotation Onthe shaft is ensured and thereby the disengag'ement of'the clutch.

The rotation of the driveri shaft at'thef'hig her speed necessary to engage a clutch and change the gear ratio is brought about by temporarily driving the shaft E through the third gearset comprising the largest gear wheel D on the driving shaft A and the smallest Wheel J on'th'e' driven shaft E. This wheel J is then coupled to the shaft E by a' fluid flywheel-operating as a clutch, "one 'part' M'of this flywheel being "fast" on the shaft while theother partfM is loose thereon and connected to the gearwheel'J. While nofl'uid is in the flywheel thegearwheel J' will be loose, but if fluid" is admitted to the fiywh'eehthegear wheel J will'becoupledto' the shaft E which will thenbe driven atahigher'speedthan ispossible through'either of the other two gearsets When the lower gear ratio is in operation, that isto say when the wheel G is coupled through "thec1utch G ,"K"to the shaft E; it is necessaryto 'hold in' its disengaged position the'movable'member' L associated with the'higherg'ear ratio wheels C; and this maybe effectedin variousiways as "may be'co'nvenient. For example a forked lever "N engaging the clutch member L may-be'manually operated soa's to "hold that 'member after its disengagement bythe action-of the-helical splines E from the 'l'ooseclutch'member H When howeverthe gear set'H, C ofthe higher 'ratiois in operation the speed at which the shaft E Willbe driven will naturally be greater than the speed at which it could b'e'driven by the lower gear ratio "set B,"G',and hence the'drag exerted on th-emov-' able clutch member G associated with the lower ratio wheel G will cause that member to be'maintained 'in 'its' disengaged position on the driven shaft.

"In the construction shown in Figures 2-7,, the

Within the casing Qare cylindrical surfaces'O 'andO adapted to cooperate with frictional members and-on clutch 'in embers enclosed in the casing whereby these i members will be caused to rotate'onandalso be "1novedaxially relatively to the gear-wheels G and f thefaxial movement being due 'to the quickpitch threads of helical splines.

The gear wheel H is' carried at' one end of a v sleeve H rotat'a'ble' on the shaft E and-having at 'the' other endspirahsplines or a quick=pitch lthre'adi at H with which engage a corresponding formation withintheclutch member H 'which' 4 is provided at one end with the dog-teeth H adapted to engage the clutch teeth P Between the periphery of the clutch member H and the casing surfaces O are disposedseveral circum- 5 ferenti'ally' extending spring actuated friction members Q, the arrangement of which can be seen in Figure 6. k The gear wheel G is mounted at one end of a s leeveG which is rotatable on the sleeve H and lo ha sat the pthenend spiral splines or a quick- 'ch "thr'ad'atjG? with which engages a similar I y 'r'n'atibri within the clutch member G On one end face of this clutch member are teeth G 'adapted' to engage the clutch teeth P on the member P carried by the shaft casing O, and at M the opposite end face of the member G are clutch teeth G.""Btween the periphery of the clutch member G and the surfaces 0 Within the casing 0" are disposed friction members R, the arrangement of which can be seen in Figure 5. It is to be otedthat th Spiralgsplines at G and H are es ectively o opposite hand. a 'Ihe gear wheelJ loose on the. shaft is conne'cted'tq thegne Dart M} of a fiuidclutch of which the other part Mis mounted on the shaft The iq n t uid to an f o h clutch is controlle d by suitable means including a sleeve jv alve M 1 so asto enable the shaft Etoibe driven when desired t hrough the gear Wheels D and J agan overspeed whereby the speed changes in the transmission through the shaft E to the impeller driv the h ,ar -b ou ht ut he clutch teeth G on the clutchvmember G iol on eci hismem riq a n S previded w th t th this me b r bei keyed to t v.1 e. a l lis nelslee e c nst n a lock- Hi i l eeha nt r a te h mes censtantly ,iviinihetean S -t. ne s an adapted also I toengage the. clutchteeth G Thus when the "toselutqhm mb fii isgcaused tmov t in h axial .'..i 9 iQn,..tQ l h el i as e i -F i 2 a 3 and withdraw its teeth G from engagement with the clutch teeth 1 the locking ring T is moved a a Tide l plbl f ei it e th. T nto e a nt with the clutch teeth G? and thereb con- Qn ct, theclutch member G to the ringS which inthis wayiprevents rotation of the clutch memberg relativelyto th e sleev e G and gear wheel G "The locking ring T is manually moved as by H ers'uchas Nfshown inQFigure 1 and also in F guies 5; and 7,: the t'wo' positions or which are indicated in' dotted lines in Figs. Z'and 3, respec- 'v rh v H iToiobltain the'hig her gearratio, the gear wheel must be coupled "to the driven shaft E by en- 'inerit of 'the't'e'ethG at one endof the clutch I 'niber; /1th; the teeth of the shaft clutch ifiernberBliToobtain the lower gear ratio, the

M 'ear wheel Hmust'be coupled to the driven shaft engagement of the teeth l l of the clutch member H with the teeth P of the shaft clutch QTojybringabogt the change to the lower speed ratio when the higher gear is in operation, the 5, parts vvill at first be in the positions. in which they are shown in Figure 2, where the shaft clutch member P is coupled through the engaging clutch teeth P 9 the member G and sleeve G to thegear wheel G. The change speed control "7Q valve M is firstactuated by means of the hand 1ev er- M which causes the hydraulic coupling MM to be filled'thereby connecting the gear Wheel J to the shaft E which is then driven at an over-speed. Since the'helical splines at 'G -are left-handed, and owing tothe action of the friction members R on the clutch member G will be caused to rotate in relation to the sleeve. G and it will be thereby.

moved in the axial direction to=the left as seen in Figs. 2 and 3 so as to disengage the clutch teeth G from the teeth P of the shaft clutch,

member; The locking ring T- is then moved "by any suitable means, such as the lever N, in the axial direction to the right asshown-in-Fig. 3,- and through the engaging teeth T G on'the one hand and'the' engagement of the teeth .T with the teeth S of the ring S the clutch member; G is prevented from further rotation relatively:-

tothe sleeve G2 thereby preventing re-engage ment of the clutch teeth G5P2 when the hydraulic coupling MM is emptied and 'thespeed of the shaft E slows down. As soon as the speed of the shaft E begins to fall below the speed at which parts are then in the positions in whichthey'are" shown in Figure 3.

To change back to the higher speed ratio, the hydraulic coupling is filled by shifting the valve M to the left and the gear wheel J thus coupled to the shaft E which is then driven at a speed higher than it can be driven by the higher gear ratio. This causes the clutch member H to move along the sleeve I-I owing to the action of the helical splines and thus the clutch teeth H are disengaged from the teeth P of the shaft clutch member P. The locking ring T is moved to the left as seen in Figure 2, thus releasing the clutch member G The hydraulic coupling is now emptied by reversing the position of the valve M and the shaft E slows down and as its speed falls below that at which the gear wheel G is being constantly driven the action of the friction members R on the surfaces cause the clutch member G to turn relatively to the sleeve G and as a result move along that sleeve and bring the teeth G into engagement with the teeth P on the shaft clutch member P, and the parts are then again in the positions in which they are shown in Figure 2.

What I claim as my invention and desire to secure by Letters Patent is:

1. A variable speed gear comprising in combination a driving shaft on which are fast at least three gear wheels of different sizes, one of these gear wheels of largest diameter serving only for driving at an over-speed while the other gear wheels function respectively for driving at different gear ratios, a driven shaft which carries loosely thereon a gear wheel in constant mesh with the said overspeed gear wheel on the driving shaft and at least two other gear wheels respectively in constant mesh with the said wheels on the driving shaft through which the driven shaft can be driven at different determined gear ratios, clutch devices respectively operative to couple selectively to the driven shaft each of the said gear wheels through which the driven shaft will be driven at a determined speed according to the gear ratio, and a clutch device whereby the said over-speed gear wheel can be temporarily coupled to the driven shaft and the latter when driven at the over-speed will cause the dissurfaces assisted pref erably by suitable shaping of the dog teeth, theeegagemettitrteaofihe'gtld thatavias t a the engagement of another of the said clutch devices-whereby the driven. shaft will be driven at v a higher orat a lower speed.

, 2. A variable speed gearcomprising in com-.

bination the parts set out in claim 1 and in which each of the devices which is operative to couple to the driven shaft a gear wheel through which,

s the-driven shaft is driven at a determined speed comprises-a member fixed on the driven shaft andia member which is loose on the drivenshaft. andconnectedto a gear wheel which will be coupled to the'shaft when the clutch members are engaged, the said loose clutch member being 0011-1 15 nectedto its gear wheel through helical splines operative to effect relative, axial movement be.-.

tween the clutch members and thereby bring them ;into engagement or disengage them.

:13; A variable speed gear comprising in com,-

bination the parts set out in claim 1 and-in which each of the clutch devices whichis operative to couple to the drivenshaft a gear wheel through which the driven shaft is drivenat a determined; speed comprises a member fixed on the driven shaft, a sleeve on which is fixed one of the said gear wheels, a clutch member connected to the sleeve. throughhelical splines, and means whereby. when the driven shaft is driven at an overspeedthe said clutch member will be caused to rotate on itssleeve relative to the geartwheel onthatsleeve and such relative rotation will cause the clutch-memberto engagewith .or be dis;

engaged from the clutch member fixed on the driven shaft.

4. A variable speed gear comprising in combination the parts as set out in claim 1 and in which when a clutch associated with one of the said gear wheels through which the said shaft is driven at a definite gear ratio is disengaged and another like functioning clutch is engaged, means are provided to prevent a change in the drive and re-engagement of the disengaged clutch member until the driven shaft has attained the overspeed necessary to cause this disengagement and reengagement.

5. A variable speed gear comprising in combination a driving shaft on which are fast at least three gear wheels of different sizes of which one having the largest diameter serves only for driving at an overspeed while the other and main transmission gear wheels function respectively for driving at different determined gear ratios, a driven shaft which carries loosely thereon a gear wheel in constant mesh with the said overspeed gear wheel on the driving shaft, a sleeve freely rotatable on the said driven shaft and having fast thereon a main transmission gear wheel in constant mesh with the first of the said main transmission wheels on the said driving shaft, a clutch member rotatably carried on the sleeve and connected thereto through helical splines so that if the clutch member is caused to rotate relatively to the sleeve it will move in the axial direction on the sleeve and then engage with or be disengaged from another clutch member which is fast on the driven shaft and thus serve to connect the said transmission gear wheel to the driven shaft, members which are frictionally in contact and are carried respectively by the driven shaft and the said clutch member on the sleeve whereby when the driven shaft is driven at an overspeed the frictional contact between these members will cause rotation of the clutch member on its sleeve and its axial movement which will engage or disengage the clutch, a second sleeve freelyrotatableon said first sleeve which is rotatable on the drivenjshait and having fast thereon a second main transmissiongear wheel, in constant mesh with the second of the said main transmission gearwheels on thedriving shaft, a clutch member rotatably carried on the said second sleeve to which it is connected through helical splines so that if the clutch member is caused to rotate relatively to the sleeve it will move in the axial direction on the sleeve and then engage with orbe disengaged, from another clutch member which is fast on the driven shaft and thus serve to connect the said second transmis sion gear wheel to the driven shaft, members which are frictionally in contact and are carried respectively by the driven shaft and the said second clutch member on its sleeve whereby when the driven shaft is driven at an overspeed the frictional contact between these members will cause rotation of the clutch member on its sleeve and its consequent axial movement which will engage or disengage the clutch, means whereby when by driving of the driven shaft at an overspeed one of the said clutch members has been caused to rotate on and move axially along its sleeve it will be coupled to its sleeve and be thereby prevented from movement relatively to its sleeve and thus maintained in the, disengaged position, means for controlling this coupling so as to enable the clutch member to be released for the rotational 'and'axial movements necessary to engage the clutch, a clutch whereby the said over.- speed gear wheel can be coupled to the driven shaft on which it is carried, and nf eansfor coiitrolling this clutch.

6, A variable speed gear comprising in combination the parts as set out in claim -5 and in which the said clutch used to couple the said overspeed gear wheel to the driven shaft is of the fluid and the clutch is allowed to empty it will become inoperative after the gear change has been ef'- 'fected.

7. A variable speed gear comprising in combination the parts "as set out in claim 5 and in which the said clutch member on the driven shaft is a single member havin clutch parts adapted to be respectively engaged by'the said first and second clutch members when moved around and along their sleeves, this single member on the driven shaft having two parts with each of which members carried by one of the said clutch members are in frictional contact, so that when the shaft'is driven at the overspeed this frictional contact will cause rotation of the clutch member on its sleeve with consequent axial movement on the sleeve.

BENJAMIN WILLIAM BARLOW.

No references cited. 

